Continuous casting mold, a shorter side thereof and method of exchanging the shorter side frame

ABSTRACT

A mold shorter side frame of a continuous casting mold is exchanged integrally as it is to enable on-line change of the thickness of the case piece. As the method, a concave portion for engaging a portion of the moving device and an attaching/detaching mechanism having a fixing jig for fixing the portion of the moving device are disposed at the back of the shorter side frame. Particularly, an attaching/detaching mechanism comprising a concave forming portion having a downwarded opening and a bolt screw passing from the back of the concave forming portion through at least a portion of said portion of the moving device is suitable.

TECHNICAL FIELD

This invention concerns a continuous casting mold such as for slabs,capable of changing the size of cast pieces and, particularly, itrelates to a movable frame for a shorter side thereof (hereinafterreferred to as a shorter side frame) and a method of exchanging thesame.

BACKGROUND ART

In recent years, casting molds for use in continuous casting apparatusfor cast pieces, particularly, large cast pieces such as slabs areconstituted such that the size of the continuously cast slabs can bechanged by displacing the position for each side of a mold duringcasting.

In the casting mold described above, the frame on the longer side of acast piece cross section (longer side frame) is made larger in the widththan that of the cast piece to be cast. Shorter side frames are putbetween the longer side frames of large width, and the shorter sideframes are connected to a shorter side frame moving device, for example,a screw type cylinder for changing the width of the cast piece. Theposition of the shorter side frame and, accordingly, the width of thecast piece can be changed by the stroke of the cylinder.

On the other hand, for the change of the thickness of the cast piece,the size is changed by changing the position for the longer side frameof the mold and exchanging the shorter side frame with other frameconforming the gap between the longer side frames.

Heretofore, the moving device and the shorter side frame have beenfixedly joined by means of a joint or the like. Upon changing thethickness of the cast piece, the mold has been detached entirely and apreviously provided substitute mold in which a shorter frame ofdifferent thickness is set has been disposed to the line. However, thecasting process has to be stopped for a long period of time by suchoperation procedures.

On the contrary, a technique aimed for simplifying the operationconcerning exchange of the shorter side frame (for the change of thecast piece thickness) of a continuous casting mold includes a continuouscasting mold capable of changing the thickness of the cast piecedisclosed in JP-A-4-224049.

In this technique, the continuous casting mold capable of changing thethickness of the cast piece comprises a longer side stationary frame anda longer side movable frame capable of opening and closing by a remotecontrol operation and a pair of shorter side frames put between thelonger side frames in which the shorter side frame comprises a fixedshorter side frame connected with a moving device and a variable shorterside frame attached to/detached from the fixed shorter side frame andsecured with a shorter side copper plate. Further, a cooling waterchannel is formed to the variable shorter side frame constituting theshorter side frame, and the water charge/discharge channel of thestationary shorter side frame and the water cooling channel of thevariable shorter side frame are engaged/disengaged with each other atthe frame mating surface. Further, the mating portion of the stationaryshorter side frame and the variable shorter side frame comprises anengaging portion, to facilitate the positioning by the engaging portion.

However, in the technique described above of adopting a double structurefor the shorter side frame, the thickness of the shorter side frameincreases in the moving direction of the shorter side frame and themoving distance of the shorter side frame for the change of the castpiece width undergoes restriction. Further, since the weight of theshorter side frames inevitably increases compared with a one piececonstitution, load is increased in a case of high speed change of widthduring casting and the large stroke for the change of width can not betaken. For extending the stroke, it is necessary to increase both thelength and the diameter of the moving device for the change of the castpiece width, which results in increased installation cost, operationcost and, maintenance cost, and loss of space.

A further problem is a danger of water leakage. In the techniquedescribed above, the variable shorter side frame is adapted to beexchanged only for the copper plate section in order to minimize theportion to be exchanged. However, since contact of cooling water withthe copper plate portion in such a structure can be attained only byproviding a cooling water channel between the variable shorter sideframe and the stationary frame, a countermeasure is required for thewater leakage in the joined portion. This requires for example, a presscylinder for pressing the stationary shorter side frame and the variableshorter side frame in order to prevent water leakage from a portionbetween both of them. However, since the continuous casting operationhandles also a powder such as continuous casting powder, obstacles suchas powder tend to intrude to the joined portion between the two frames,which requires utmost care and long time for the joining operation.Further, since the continuous operation time (period) is increased alongwith increasing life of the mold, seal for cooling water at the joinedportion deteriorates sooner. In a case where the water leakage shouldoccur by the failure of the pressing cylinder, intrusion of obstacles ordegradation of the seal, this brings about seizure of the copper plateand, depending on the case, inflow of a great amount of water into themold to possibly cause a worry of steam explosion.

DISCLOSURE OF THE INVENTION

This invention intends to solve the foregoing problems and provide amethod of exchanging, in-situ the entire shorter side frame, that is,the variable frame corresponding portion (copper plate) and thestationary frame corresponding portion (back frame) integrally withoutdividing them. Further, it intends to provide a shorter side frame withimproved attaching/detaching mechanism relative to the moving device inorder to attain the method, as well as a casting mold using such ashorter side frame.

In accordance with this invention, the above mentioned object isattained by constituting a connection portion between a shorter sideframe of a continuous casting mold and a moving device for changing thewidth of the shorter side frame (stepping cylinder or the like) with aconcave shape structure and inserting a fixing jig (particularly, afixing jig capable of inserting from the upper end side of the mold)thereby joining to fix the moving device and the shorter side frame.

That is, this invention provides a continuous casting mold comprising apair of longer side frames in which at least one of them is movable in aforward-to-backward direction, a pair of shorter side frames put betweenthe pair of longer side frames and movable in the forward-to-backwarddirection and, a pair of moving devices for moving each of the shorterside frames in the forward-to-backward direction respectively in whichthe shorter side frames and the moving devices for moving the same areengaged respectively by way of one or more of attaching/detachingmechanisms disposed at the back of the shorter side frame, theattaching/detaching mechanism has a concave forming portion having aconcave portion engaging a portion of the moving device, and at leastone of the attaching/detaching mechanisms has a fixing jig for fixingthe portion of the moving device to the concave forming portion on everyshorter side frame. Referring to the forward-to-backward direction, itis defined that the side of the cast piece in each frame is defined as aforward direction and the side on the rear face of the frame is definedas the backward direction.

In this case, a constitution in which the concave forming portion has adownwarded opening portion, and the fixing jig is a bolt screw passingfrom above through the back of the concave forming portion and at leasta portion of the moving device is particularly preferred. Further, it ispreferred that the gap of the walls of the concave forming portionsandwiching a portion of the moving device is made larger by 0.1 to 0.4mm (preferably, 0.1 to 0.2 mm) than the size for the portion of themoving device. Further, it is also preferred that the portion of themoving device fixed to the concave portion of a attaching/detachingmechanism having the fixing jig has a substantially square cylindricalshape (square pin shape).

Further, in the structure of the attaching/detaching mechanism, theopening of the concave forming portion is directed to the back of theshorter side frame, a portion of the lower wall of the concave formingportion is opened and, further, the fixing jig is a cotter inserted fromabove.

In any of the embodiments described above, it is preferred that theshorter side frame has cooling water channels at the inside of theintegrated frame.

Further, this invention provides a shorter side frame constituting amold for use in continuous casting, comprising one or more ofattaching/detaching mechanisms to engage a moving device for moving theshorter side frame in a forward-to-backward direction at the back of theshorter side frame, in which the attaching/detaching mechanism has aconcave forming portion having a concave portion in engagement with aportion of the moving device and at least one of the attaching/detachingmechanisms has a fixing jig for fixing the portion of the moving deviceto the concave forming portion. Preferred embodiments for the shorterside frame, the attaching/detaching mechanism and the like are identicalwith those in the invention for the casting mold.

This invention further provides a method of exchanging, in-situ, a pairof engaged shorter side frames (referred to as A) with another pair ofshorter side frames (referred to as B) in a continuous casting moldhaving a pair of longer side frames in which at least one of them ismovable in a forward-to-backward direction, a pair of shorter sideframes put between the pair of the longer side frames and movable in theforward-to-backward direction and moving devices engaged by way of oneor more of attachment/detachment mechanisms disposed respectively to theshorter side frame for moving the shorter side frames respectively inthe forward-to-backward direction wherein the method comprises, a stepof once stopping casting, a step of moving the shorter side frames A bythe moving devices in the backward direction and stopping the same atpredetermined exchange positions respectively, a step of moving at leastone of the longer side frames to an aimed position in aforward-to-backward direction thereby setting an aimed slab thickness, astep of releasing the attaching/detaching mechanisms for the shorterside frames A respectively to detach the entire shorter side frames Afrom the moving devices by the attaching/detaching mechanismsrespectively, a step of engaging the entire shorter side frames B havinga width corresponding to the aimed slab thickness to the moving devicesby way of the attaching/detaching mechanisms for the shorter side framesB respectively, a step of moving the shorter side frames B by the movingdevices respectively in the forward direction thereby setting apredetermined slab width and a step of starting casting again. Thetiming for the movement of the longer side frame may be set properlydepending, for example, on whether the thickness of the slab is changedin the increasing direction, or in the narrowing direction toward thereducing direction, or the movement may of course be conducted forseveral times.

In this case, it is preferred that the method further includes, inaddition to the step described above, a step of stopping the supply ofcooling water to the shorter side frames A respectively before detachingthe shorter side frames A from the moving devices, and detaching thesupply pipes for cooling water to the shorter side frames A from theshorter side frames A respectively and further includes a step ofconnecting the cooling water supply pipes to the shorter side frames Brespectively after engagement of the shorter side frames B to the movingdevices, and starting supply of cooling water to the shorter side framesB respectively.

According to this invention, in the continuous casting mold, the copperplate and the back frame of the shorter side frame can be exchangedin-situ easily while leaving them integrally as it is. Accordingly, forchanging the thickness of the cast piece, since the shorter side framecan be exchanged on-line in a short period of time, on-line change ofthe cast piece thickness is possible.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a side elevational view of a first embodiment according tothis invention.

FIG. 2 is an enlarged view for an attaching/detaching mechanism in thefirst embodiment according to this invention.

FIG. 3 is a plan view of a first embodiment according to this invention.

FIG. 4 is an explanatory view for the attaching operation of a shorterside frame in the first embodiment according to this invention.

FIG. 5 is a detailed view (side elevational view) for pipe installationin the first embodiment according to this invention.

FIG. 6 is a detailed view (cross sectional view as viewed from the backof the shorter side frame) for pipe installation in the first embodimentaccording to this invention.

FIG. 7 is a detailed view (plan view) for pipe installation in the firstembodiment according to this invention.

FIG. 8 is a side elevational view of a second embodiment according tothis invention.

FIG. 9 is a plan view of the second embodiment according to thisinvention.

FIG. 10 is an explanatory view for the attaching operation of a shorterside frame in the second embodiment according to this invention.

FIG. 11 is a detailed view (side elevational view) for pipe installationin the second embodiment according to this invention.

-   1 mold-   2 longer side frames-   2 a longer side frame (stationary side)-   2 b longer side frame (movable side)-   3 longer side frame moving device-   4 rod-   5 worm jack-   10, 10 a, 10 b, 10′, l0 a′ shorter side frame-   11 surface of the shorter side frame-   12 rear face of the shorter side frame-   13, 13′ attaching/detaching mechanism (upper side)-   14, 14 a bolt (fixing jig)-   15, 15′ concave forming portion (upper side)-   16, 16′ concave portion (upper side)-   17, 17 b concave forming portion (attaching/detaching mechanism)    (lower side)-   18 concave portion (lower side)-   19, 19 a cotter. (fixing jig)-   20 stepping cylinder (upper side)-   21, 21′ rod top end pin (upper side)-   22 rod (upper side)-   23 stepping cylinder (lower side)-   24 rod top end pin (lower side)-   25 rod (lower side)-   26, 26′ moving device-   27 bolt hole-   27 a bolt hole (concave forming portion)-   27 b bolt hole (rod top pin)-   28 mold frame upper end face-   31 mold copper plate-   32 cooling water channel (on the side of the copper plate)-   33 cooling water channel (on the rear side)-   34 mold cooling water supply hose-   35 coupling (for mold cooling water supply)-   36 spray cooling water (Water for cooling cast slab by spraying)    supply hose-   37 coupling (for spray cooling water supply)-   38 spray type cooling device-   39 foot roll (support roll)-   41 mold movable cover-   42 mold stationary cover-   43 cooling water channel (for spray cooling water)-   44 mold cooling water discharge hose-   45 coupling (for mold cooling water discharge)-   46 cooling water supply port (for mold cooling water)-   47 cooling water supply port (for spray cooling water)-   48 cooling water discharge port (for mold cooling water)-   50–54 arrow (indicating movement)-   60 water flow (mold cooling water)-   61 water flow (spray cooling water)-   70 opening (for mold cooling water supply)-   71 opening (for mold cooling water discharge)-   72 opening (for spray cooling water supply)-   73 pipe (for supplying mold cooling water to the side of copper    plate)-   74 opening portion (for supplying spray cooling water) a mold    thickness

BEST MODE FOR PRACTICING THE INVENTION

FIG. 1 to FIG. 7 show a first preferred embodiment according to thisinvention. FIG. 1 is a side elevational view for the first embodiment,FIG. 2 is an enlarged view for an attaching/detaching mechanism, FIG. 3is a plan view showing the first embodiment, FIG. 4 is an explanatoryview showing the attaching operation thereof and FIG. 5 to FIG. 7 aredetailed views showing the connection of water cooling pipes

A continuous casting mold 1 has, for example, as shown in FIG. 3, a pairof longer side frames 2 comprising a stationary side 2 a and a movableside 2 b, which are clamped by way of shorter side frames 10 puttherebetween to form a space of a rectangular cross section, and moltenmetal is poured from a portion thereabove and a slab is drawn downwardlyto conduct continuous casting. The surface 11 of the shorter side frameis defined as a casting side and the rear side 12 is defined as anopposite side. In each of the frames, a copper plate 31 for cooling isdisposed on the side of the cast piece.

As shown in FIG. 1 to FIG. 3, a moving device 26 has an upper steppingcylinder 20, a rod (upper rod) 22 as a movable part of the upperstepping cylinder 20, an (upper) rod top end pin 21 situated at the topend of the upper rod 22, a lower stepping cylinder 23, a rod (lower rod)25 as a movable part of the lower stepping cylinder 23, a (lower) rodtop end pin 24 situated at the top end of the lower rod 25.

In this embodiment, the rod top end pins 21 and 24 correspond to aportion of the moving device (it is not necessarily a top end buthereinafter also referred to as a top end portion of the moving devicefor the simplicity) to be engaged to a concave forming portion of anattaching/detaching mechanism to be described later. In this embodiment,the upper top end pin 21 is made into a substantially square cylindricalshape for the engaging portion with the shorter side frame and into asubstantially circular cylindrical shape for the connection portion withthe rod 22. Further, the lower top end pin is formed into asubstantially circular cylindrical shape.

During continuous casting, the position for the shorter side frame 10can be changed by loosening the clamping for the longer side frame 2 andadvancing or retracting the stepping cylinders 20, 23 to change thewidth of the slab.

On the other hand, the thickness of the slab is changed, for example, bythe following procedures. Referring to an example of FIG. 3, one of thelonger side frames (movable side 2 b) is joined by way of a rod 4passing through the other of the frames (stationary side 2 a) to a wormjack 5. The movable side longer frame 2 b moves forward and backward bya longer frame moving device 3 comprising the worm jack 5 and the rod 4to change the thickness for the cross section of the mold space. At thesame time, the shorter frame 10 is replaced with another shorter frameof different width. In this invention, exchange of the shorter frame 10can be conducted on-line in which an upper attaching/detaching mechanism13 and a concave forming portion (lower side) 17 constituting the lowerattaching/detaching mechanism are disposed at the back 12 of the shorterframe 10.

As shown in FIG. 2 in an enlarged scale, the upper attaching/detachingmechanism 13 comprises a concave forming portion 15 having a concaveportion 16 and a bolt 14 as a fixing jig. The concave forming portion 15is attached with the opening being downwarded to the shorter side frameand the concave forming portion has a shape capable of engaging theupper rod top end pin 21 by the concave portion 16.

The bolt 14 passes through at least a portion of the top end pin 21 fromthe back part (upper) of the concave forming portion 15 along a bolthole 27, thereby fixing the top end pin 21 to the concave formingportion. By the use of the bolt as a fixing jig, an operation spacerequired for the fixing operation by the fixing jig can be madeextremely small.

The bolt hole 27 a apertured in the concave forming portion 15 is madesomewhat larger than the bolt diameter. A preferred bolt hole size isabout bolt diameter +0.1 to 0.2 mm. Further, the threads correspondingto the threads of the bolt are formed only to the bolt hole 27 bapertured in the top end pin. The bolt hole 27 b may penetrate the topend pin.

The concave portion 16 preferably has a substantially identical shapewith that of the pin to be engaged (to such an extent as capable ofattaching and detaching). It is preferred in this embodiment to definesuch shape and size as forming a gap of 0.1 mm or more in total betweenthe wall of the concave forming portion 15 and the pin 21 when they areengaged. This is because powdery matters or the like are scattered andsuspended at the periphery of a continuous casting facility as describedabove and, unless the gap is disposed, a difficulty may be possiblycaused for the attachment/detachment when the powder should intrude intothe concave portion.

When the gap is excessively large, positioning of the fixing jig(positioning for the bolt hole in this case) is complicated and also ittends to cause rattling. Consequently the upper limit for the gap is setto about 0.4 mm, preferably, about 0.2 mm. Conversely, when the upperlimit of the gap is 0.4 mm or less, centering is facilitated uponinsertion of the bolt 14 through the bolt hole 27 a provided with themargin as described above.

In this embodiment, it is preferred that the top end portion of themoving device fixed by the fixing jig has a substantially squarepin-like cross sectional shape (substantially square cylindrical shape).This is due to the following reasons.

One of the reasons is that fixing by the bolt screw is more reliable inthe case of the square cylindrical shape compared with the case of thecircular cylindrical shape.

Another reason is that the positioning function is improved. It ispreferred that at least one of the attaching/detaching mechanisms alsohas a function of vertical positioning for the shorter frame and it ispreferred that the attaching/detaching mechanism having the fixing jigis provided with the function of the vertical positioning (since theportion fixed to the fixing jig is least moveable). For the purpose ofvertical positioning, the contact portion between the concave portionand at least the upper surface of the top end pin is preferably planer.On the other hand, for providing also the function offorward-to-backward positioning (forward-to-backward direction of theshorter frame) with such a shape, it is preferred that the shape isplanar also in the forward-to-backward direction. Accordingly, thesquare cylindrical shape is a most simple shape for satisfying thepreferred conditions described above. Each of the corners for the squarecylinder may be chamfered with no problems.

In a case of adopting the top end of the generally square cylindricalshape, since it particularly tends to undergo the undesired effect ofscattered powder, it is strongly recommended to ensure the gap.

With a view point of workability, it is preferred to attach a pin of agenerally circular cylindrical shape to the top end of the rod and,subsequently, fabricating the engaging portion with the shorter frameinto a generally square cylindrical shape. Accordingly, the joinedportion with the rod may be of a generally cylindrical shape.

The lower attaching/detaching mechanism substantially comprises only theconcaved forming portion 17 (with downwarded opening). In a case of thisembodiment using a generally square cylindrical pin as the top end forengagement with the upper attaching/detaching mechanism having thefixing jig, it is preferred that the top end of the lower moving deviceis a pin of a generally circular cylindrical shape and the concaveportion 18 is a U-shaped groove (the bottom of the indent has asubstantially semi-circular sectional shape). The constitution describedabove is desirable because in the non-fixed type attaching/detachingmechanism (attaching/detaching mechanism having no fixing jig),positioning (preference being given, particularly, to positioningaccuracy in the forward-to-backward direction) is facilitated and thepositional accuracy in the forward-to-backward direction is notdeteriorated so much when scattered powder or the like is involved.

FIG. 4 is an explanatory view for the attachment of the shorter frame10. A shorter frame 10 a shown by an imaginary line is lowered as shownby an arrow 54 such that the lower concave forming portion 17 b situatesbetween the upper and lower rods 22 and 25 (that is, to a position notinterfering the rods) (10 b). Subsequently, after moving the shorterside frame 10 b rightwardly as shown by an arrow 50, it is moveddownwardly and the upper and lower moving device top end portions (pins)21, 24 are engaged with and attached to the upper and the lowerattaching/detaching mechanisms 13, 17 respectively.

In FIG. 4, an upper end face position 28 for the mold frame is shown forthe reference.

In this case, it is preferred that the rod top end pin 21 of the upperstepping cylinder 20 and the rod top end pin 24 of the lower steppingcylinder 23 are situated each at a position advanced from the limitposition for the retracting stroke of the stepping cylinder to such anextent as capable of ensuring the operationability. In this embodiment,they were advanced each from the retraction limit by 200 mm. It ispreferred that both of the upper and lower pins are stopped generally atan identical position (for the forward-to-backward direction of theshorter side frame).

After engaging the upper and the lower top end portions (top end pins)to respective concave forming portions 15, 17 of the upper and the lowerattaching/detaching mechanisms, the bolt 14 a is passed from above asshown by an arrow 51 through bolt holes 27 a and 27 b formed to theupper attaching/detaching mechanism and the upper top end portionengaged therewith respectively and the bolt 14 is clamped. The bolt 14may be clamped manually or clamped by using a machine. After attachingthe shorter side frame, a cooling water piping to be described later isconnected optionally to flow a cooling water and then the shorter frameis moved till the casting position (aimed lateral position of slab) inthe forward-to-backward direction of the shorter side frame.

Upon detaching the shorter side frame, the procedures are reversed. Thatis, the shorter side frame is moved at first in the forward-to-backwarddirection to a position suitable to exchange and stopped at thatposition. Successively, optional cooling water is stopped and thecooling water piping is detached. Subsequently, the bolt is loosened andremoved and then the shorter side frame may be moved and pulled up inthe direction opposite to the arrows 50 and 54.

Movement of the shorter side frame upon attaching or detaching is notnecessarily restricted to the method described above so long as it canmove with no interference to the longer side frame or the moving device(stepping cylinder in this embodiment) and it may also include movement,for example, in the oblique direction.

As a matter of course, upon attaching or detaching the shorter sideframe, it is necessary that the distance between the longer side framesis made larger than the thickness a (refer to FIG. 3) of the shorterside frame by the moving device for the longer side frame (worm jack inthis embodiment) 3. After the exchanging operation for the shorter sideframe, the shorter side frame is sandwiched by a predetermined force bythe moving device 3.

With the structure and procedures described above, the shorter sideframe can be integrally attached or detached extremely simply and theshorter side can be changed on-line.

FIG. 5 is a side elevational view for showing attachment and detachmentof a cooling water pipes, and FIG. 6 is a cross sectional view takenalong a plane A–A′ as viewed from the back of the shorter side of theframe. Further, FIG. 7 is a plan view taken along a plane B–B′ in FIG. 5from above. The shorter side frame 10 has a mold copper plate 31 on thesurface 11 and has a cooling water channel 32 on the side of the copperplate between the copper plate 31 and the frame main body. Further, italso has a rear side water channel 33 for supplying cooling water to thecooling water channel 32 in the inside of the frame.

The cooling water channel 32 on the side of the copper plate ispreferably formed as a plurality of grooves to the copper plate as shownin FIG. 7 (in FIG. 6, front elevational view, only the outer edge isshown with no details) but it is not restrictive. The water channels 33at the back are disposed by the number of two in this embodiment but thenumber is not restricted particularly so long as a required water flowrate can be ensured.

When the shorter side frame is attached, a mold cooling water supplyhose 34 is attached to a mold cooling water supply port 46 by a coupling35, and a mold cooling water discharge hose 44 is attached to a moldcooling water discharge port 48 by a coupling 45 thereby connectingcooling pipe. Then, supply of the cooling water is started.

The supplied cooling water passes through a mold cooling water supplyopening 70 and through the cooling water channels 33 at the back andenters by way of pipe 73 (mold cooling water supply pipe on the side ofthe copper plate) in the lower portion of the frame into the coolingwater channels 32 as water flow of mold shown by an arrow 60 in FIG. 5to FIG. 7. Cooling water entering to the copper plate flows upwardly inthe cooling water channels 32 on the side of the copper plate and thendischarged through the mold cooling water discharge opening 71 into thedischarge hose 44.

On the other hand, when the shorter side frame is detached, afterstopping the supply of cooling water, the coupling 35 for the moldcooling water supply hose 34 is detached from the cooling water supplyport 46 and, in the same manner, the coupling 45 for the mold coolingwater discharge hose 44 is detached from the cooling water dischargeport 48.

The cooling water supply hose 34 and the discharge hose 44 may beattached or detached manually or mechanically and there is norestriction for the order thereof. Although not illustratedparticularly, the cooling water supply mechanism may be a generalequipment.

The spray cooling water channel 43 for cooling the lateral surface ofthe continuously cast slab may sometimes be disposed to the shorter sideframe. Also in this case, the spray cooling water hose 36 may beattached or detached by way of the coupling 37 to the spray coolingwater supply port 47 in the same manner. The timing for attachment anddetachment, as well as supply and stop of cooling water may be identicalwith that for cooling water for the frame.

The stream of the spray cooling water upon connection flows through aspray cooling water supply opening 72 into the water channels (which mayalso be pipeline) in the shorter side frame and by way of an opening 74for the spray cooling water spray supply in the lower portion of theshorter side ladle frame to a spray type cooling device 38 as shown byan arrow 61 (spray cooling water flow) in FIG. 5 to FIG. 7.

As has been described above according to this invention, since thecooling water seal for the short side frame is not attached or detachedupon attachment and detachment of the cooling water piping, noparticular consideration is required for the seal leakage upon exchangeof the shorter side frame, and the seal can be always kept intact.Further, the operation for attaching·detaching the cooling water pipingis also simple.

In FIG. 5, 39 denotes a foot roll (support roll for preventing bulgingor the like), which is preferably disposed to the shorter side frame inview of smooth continuous casting.

Further, for preventing heat dissipation of molten steel form the uppersurface of the mold (prevention of temperature lowering) and preventingintrusion of obstacles such as powder for continuous casting, a moldstationary cover 42 and a mold movable cover 41 may sometimes bedisposed aside above the shorter side frame, and they sometimesinterfere the carrying space for the exchange of the shorter side frame.In this case, the movable cover 41 may be once detached before theexchange of the shorter side frame and attached again after thecompletion of exchange. It is not usually necessary to detach thestationary cover 42 entirely but the cover plate in the upper portionmay be displaced as required.

FIG. 8 to FIG. 11 show a second preferred embodiment according to thisinvention. FIG. 8 is a side elevational view of the second embodiment,FIG. 9 is a planer view thereof, FIG. 10 is an explanatory view showingthe attaching operation thereof and FIG. 11 is a detailed view (sideelevational view) showing the connection of water cooling pipings.

Continuous casting mold 1, a pair of longer side frames 2, a movingdevice 26′ and the like are identical with those in the first embodimentexcepting for the shape of the top end portion (pin) 21′ of the uppermoving device. Further, also the shorter side frame 10′ is identicalwith that of the first embodiment except for the structure of the upperattaching/detaching mechanism 13′ (FIG. 8, FIG. 9).

As can be seen from FIG. 8, in this embodiment, the opening of theconcave forming portion 15′ in, the attaching/detaching mechanism 13′,is directed to the rear face 12 of the shorter side frame 10′, and aportion of the lower wall of the concave forming portion 15′ is openedand, further, the fixing jig is a cotter 19 inserted from above.

In other words, it may be said that the concave forming portion 15′ hasa shape comprising a horizontal protrusion, a suspended portion at thetop end thereof and a short horizontal turn-back at the lower end of thesuspended portion. Further, the shape may also be expressed as adownwardly opened hook, a cramp-shaped configuration with shorter lowerside, or a J-shaped configuration (which may be angled).

The top end pin 21′ is engaged to the concave portion 16′ at the bottomof the hook. That is, the rod top end pin 21′a is engaged in such amanner that it is embraced to the inside of the shorter side of thecramp-shaped configuration.

Then, a cotter 19 is inserted between the rod top end pin 21′ engaged tothe inside of the shorter lower side of the cramp-shaped configurationand the rear face 12 of the shorter side frame 10′ to prevent detachmentbetween the pin and the hook (that is, the pin is fixed to the concaveforming portion 15′).

The cotter is vertically movable, has a taper on the lateral surface forinserting and detaching from above and it is inserted by being enforceddownward between the rod top end pin 21′ and the rear face 12 of theshorter side frame 10′, to fix the rod top end pin 21′ to the concaveforming portion 15′.

It is preferred that the rod top end pin 21′ is of a substantiallycircular cylindrical shape in view of the operability of the engagingoperation but a portion thereof in contact with the cotter 19 ispreferably formed into a square cross sectional shape so as to be wellfitted with the cotter 19. A handle or attaching tool not illustrated ispreferably attached to the cotter 19 so that it is inserted or detachedmanually.

FIG. 10 is an explanatory view for the attachment of the shorter sideframe 10′. In the same manner as for the first embodiment, afterpositioning such that the lower concave forming portion 17 a situatesbetween the upper and lower rods 22 and 25 (10 a′) (drawing beforelowering is not shown), the shorter frame 10 a′ is moved rightwardly andthen downwardly as shown in arrow 52 and then upper and lower movingdevice top ends (pins) 21′, 24 are engaged with and attached to theupper and the lower attaching/detaching mechanisms 13′, 17 respectively.

Upon preceding positioning for the top end pin, the rod top end pin 21′of the upper stepping cylinder 20 is stopped at a position advancedslightly from the rod top end pin 24 of the lower stepping cylinder 23and, when the lower rod top end pin 24 engages the concave formingportion 17 of the lower attaching/detaching mechanism, the rod top endpin 21′ of the upper stepping cylinder is retracted. Then, the pin 21′is embraced inside of the hook-shaped concave forming portion 15′. Then,the cotter 19 a is inserted from above as shown by an arrow 53. When theinserted cotter 19 is pressed down, fixing between the pin and the hookis completed.

When the shorter side frame 10′ is detached, the procedures describedabove may be reversed. In this case, after removing the cotter 19upwardly, the upper rod top end pin 21′ is advanced slightly by whichthe detaching operation in the upper attaching/detaching mechanismproceeds smoothly.

Accordingly, also in this embodiment, the shorter side frame can beattached or detached quite simply, and the shorter side frame can beexchanged on-line.

FIG. 11 shows attachment and detachment of cooling water pipings. Theconstitution for each of the portions regarding attachment anddetachment of the cooling water pipings is identical with that of thefirst embodiment and the attaching and detaching procedures are alsoidentical.

Also in this second embodiment, since the cooling water seal for theshorter side frame is not detached or attached by attachment anddetachment of the cooling water pipings upon exchange of the shorterside frame, no particular consideration is required upon exchange of theshorter side frame and the seal is always kept intact.

The two embodiments have been described as above but the invention isnot restricted thereto.

For example, it is not always necessary to adapt the stepping cylinderas the moving device for the shorter side frame but an ordinaryhydraulic cylinder (positional detection is conducted, for example, by acombination of a guide rod and a positional sensor), a worm jack and ahydraulic motor (positional detection is conducted, for example, by arotation detection device) or a silnuck cylinder can be used. However,the stepping cylinder is particularly preferred since the positioningaccuracy is high. Further, each of the devices described above can beused also as the moving device of the longer side frame and the wormjack is suitable in view of installation and operation space or power.

Further, while two stepping cylinders consisting of upper and lowerstepping cylinder have been adopted as the moving device, the number ofthe moving mechanisms such as the stepping cylinders has no particularrestriction. However, upon change of the slab width during continuouscasting, it is preferred to gradually change the thickness by oncetilting the shorter side frame and, for this purpose, it is preferredthat at least two (upper and lower) moving mechanisms are provided. Onthe other hand, there is no substantial merit of disposing them by thenumber of three or more, the moving device is preferably disposed by thenumber of two in view of the cost excepting for a case, for example,where the weight of the shorter side frame is particularly heavy.Accordingly, it is also preferred that the attaching/detachingmechanisms are disposed at two positions that is upper and lowerposition.

Upon engagement with two or more moving mechanisms, the fixing jig maybe disposed to any of the attaching/detaching mechanisms. However, it isgenerally preferred to provide the fixing jig to the attaching/detachingmechanism situated to the upper position in view of the operability andeasy confirmation.

Further, with a view point of the operability, the fixing jig ispreferably disposed by one to each of the shorter side frames but it maynaturally disposed two or more attaching/detaching mechanisms.

The attaching/detaching mechanism to which the fixing jig is disposedmay be any mechanism not being restricted to the example describedabove. For example, an engaging method of sandwiching the moving devicetop end (pin) may be used. However, it is preferred to be based on theshape of the hook which engages the top end since this facilitatescompatibility between the attaching and detaching operability and thefixing performance. As a variation for the hook-shaped form, it may beconsidered a method of forming openings of the J-shaped configuration indifferent upper and lower directions between right and left sides in thesecond embodiment and moving the pin to the engaging position by therotation of the rod. However, the first and the second embodiments aresuperior in view of the operability.

For the fixing jig, a key, or a usual wedge, latch or a combinationthereof (for example, wedge and bolt) may be considered in addition tothe example described above. It is preferred that the fixing jig of atype to be inserted from above with a view point of the operability andthe confirmation of the fixing state.

The attaching/detaching mechanism not provided with the fixing jigpreferably has a downwarded concave forming portion simply in view ofthe operability and the cost, with no particular restriction thereto.For example, attachment and detachment are possible by the mechanismhaving a concave forming portion in the forward-to-backward direction ofthe shorter side frame. However, when the concave forming portion isdisposed in the forward-to-backward direction, since large force exertsin the forward-to-backward direction, for example, in a case of changingthe width of the cast piece during casting, the fixing jig (ofattaching/detaching mechanism with fixing jig) suffers from a burden torequire a strength for the fixing tool. Therefore, the downwardedconcave forming portion is most preferred.

The top end of the moving device for engagement with theattaching/detaching mechanism is not restricted to the pin as describedabove, but a recess may be formed directly to the rod top end so thatthe attaching/detaching mechanism sandwiches the recess. However, thepin is most preferred in view of easy fixing and strength.

The shorter side frame may be provided with other auxiliary facilityuseful for the continuous casting operation in addition to the coolingspray or the foot roll described above. For example, thermo-couple thatforecast brake-out may be attached to the shorter side frame. In thiscase, wirings may be disconnected or connected at the same timing asthat for the attachment and detachment of the cooling water pipings. Thefoot roll is not restricted only to a single stage but it may bedisposed by plural stages in accordance with the casting speed or thelike.

Further, the cooling water channels (pipes) in the shorter side frameare not restricted to the illustrated example but the water channels inthe copper plate may be of a large width. However, so long as it hasbeen known, the illustrated type is most efficient. Further,supply·discharge ports of mold cooling water may be attached to thelower end part of the shorter side frame (the system are often adaptedso far) but it is preferred to attach them to the upper end part in viewof the operability. Instead of the discharging path for cooling water,discharged water may be supplied, for example, to the spray coolingwater channel.

For the longer side frame, it is general to make one of them stationaryand the other of movable but it is theoretically possible to make bothof them movable. However, the longer side frame is an important facilityto form a path line for the cast piece and it is preferred to fix one ofthem in view of the quality control such as for size and shape sincecentering is easy upon mold exchange.

The method according to this invention is suitable to continuous castingof slabs. While it may be applicable also to cast pieces of shapes otherthan the slabs, for example, to bloom billets, but the roll adjustmentfor the exclusive portion just beneath the mold is difficult.Accordingly, application to the continuous casting of slabs is mosteffective.

For the size of the slab, a width from 800 to 2500 mm is a suitablerange but the range is not restrictive. In addition, a wide degree offreedom exists for the thickness in view of the feature of thisinvention and, for measure use, it is generally from 200 to 300 mm. Thisinvention provides a large merit, particularly, to a continuous castingfacility handling many kinds of thickness.

EXAMPLE

A shorter side frame and a continuous casting mold in accordance withthe first embodiment (FIGS. 1 to 7) according to this invention wereapplied to a continuous casting line of steel slabs. In this case, thecross sectional size of the slab includes 1800 to 2500 mm width, andthree kinds of thickness of 215 mm, 260 mm and 310 mm. The continuouscasting speed was set to about 1.0 m/min. Each four sets of the shorterside frames were provided on each thickness and the frequency ofexchange for the shorter side frame was about 15 times/month. The gapbetween the top end pin 21 and the concave forming portion 15 was 0.2 mmand bolt fixing/releasing operation was conducted by manual operation.Further, a portion of the upper top end pin 21 in engagement with theconcave forming portion 15 was formed as a square cylindrical shape withabout 50 mm for one side (chamfered) and other portion and the lower topend pin 24 are formed each into a circular cylindrical shape of about 60mm diameter.

Change of the set thickness in the conventional mold was conducted byremoving the mold main body by hoisting using a crane and setting asubstitute mold again which was previously set with a shorter side frameof another thickness. Therefore, it took for about 90 min for exchangeincluding setting of crane, entire removal of covers, the stand-by timefor steam countermeasure upon lifting and the like.

However, in this embodiment, since, the setting for the thickness can bechange only by the exchange of the shorter side frame, the required timeis about 30 min or slightly less (about 15 min per one side) whichgreatly shortens the time. Further, since steams and the like are notreleased because the cover or the like is not detached, an evaluationthat the working circumstance was improved has been obtained fromoperators.

INDUSTRIAL APPLICABILITY

According to this invention, since the connection mechanism between theshorter side frame and the moving device is formed into a concave shapestructure to adopt a fixing system capable of easy attaching anddetaching, the shorter side frame can be exchanged on-line easily and ina short period of time, which also make the change of the mold thicknessin a short time.

Further, since the shorter side frame has a integral structure, there isno worry at all for the sealing failure for cooling water between thesurface and the rear face of the shorter side frame, compared withexistent divisional exchange type.

Further, since the thickness of the shorter side frame can be reduced,this invention can be applied even to a case of modifying the existentcontinuous casting mold without narrowing the castable slab width.

1. A shorter side frame for constituting a mold for use in continuouscasting, comprising one or more of attaching/detaching mechanisms toengage a moving device for moving the shorter side frame in aforward-to-backward direction at the back of the shorter side frame, inwhich each of the at least one of the attaching/detaching mechanisms hasa concave forming portion having a concave portion in engagement with aportion of the moving device and at least one of the attaching/detachingmechanisms has a fixing jig for fixing a portion of the moving device tothe concave forming portion, wherein the concave forming portion has adownward opening portion, and the fixing jig is a bolt screw passingfrom above through the back of the concave forming portion and at leasta portion of the moving device.
 2. A shorter side frame for constitutinga mold for use in continuous casting, comprising one or more ofattaching/detaching mechanisms to engage a moving device for moving theshorter side frame in a forward-to-backward direction at the back of theshorter side frame, in which each of the at least one of theattaching/detaching mechanisms has a concave forming portion having aconcave portion in engagement with a portion of the moving device and atleast one of the attaching/detaching mechanisms has a fixing jig forfixing a portion of the moving device to the concave forming portion,wherein the opening of the concave forming portion is directed to theback of the shorter side frame, a portion of the lower wall of theconcave forming portion is opened and, further, the fixing jig is acotter, wherein the cotter is inserted from above between the portion ofthe moving device and the shorter side frame.
 3. A continuous castingmold comprising: a pair of longer side frames in which at least one ofthe longer side frames is movable in a forward-to-backward direction, apair of shorter side frames put between the pair of longer side framesand movable in the forward-to-backward direction and, a pair of movingdevices for moving each of the shorter side frames in theforward-to-backward direction respectively in which the shorter sideframes and the moving devices for moving the shorter side frames areengaged respectively by way of one or more attaching/detachingmechanisms disposed at the back of the shorter side frames, each of theat least one of the attaching/detaching mechanisms has a concave formingportion having a concave portion engaging a portion of the movingdevice, and at least one of the attaching/detaching mechanisms has afixing jig for fixing the portion of the moving device to the concaveforming portion on every shorter side frame, wherein the concave formingportion has a downward opening portion, and the fixing jig is a boltscrew passing from above through the back of the concave forming portionand at least a portion of the moving device.
 4. A continuous castingmold as defined in claim 3, wherein the gap of the walls of the concaveforming portion sandwiching the portion of the moving device is madelarger by 0.1 to 0.4 mm than the size for the portion of the movingdevice.
 5. A continuous casting mold as defined in claim 3, wherein theportion of the moving device fixed to the concave portion of anattaching/detaching mechanism having the fixing jig has a substantiallysquare cylindrical shape.
 6. A continuous casting mold as defined inclaim 3, wherein the shorter side frame has cooling water channels atthe inside thereof.
 7. A continuous casting mold as defined in claim 3,wherein a supply port and/or discharge port of the cooling water channelis disposed to the upper end part of the shorter side frame.
 8. Acontinuous casting mold comprising: a pair of longer side frames inwhich at least one of the longer side frames is movable in aforward-to-backward direction, a pair of shorter side frames put betweenthe pair of longer side frames and movable in the forward-to-backwarddirection and, a pair of moving devices for moving each of the shorterside frames in the forward-to-backward direction respectively in whichthe shorter side frames and the moving devices for moving the shorterside frames are engaged respectively by way of one or moreattaching/detaching mechanisms disposed at the back of the shorter sideframes, each of the at least one of the attaching/detaching mechanismshas a concave forming portion having a concave portion engaging aportion of the moving device, and at least one of theattaching/detaching mechanisms has a fixing jig for fixing the portionof the moving device to the concave forming portion on every shorterside frame, wherein the opening of the concave forming portion isdirected to the back of the shorter side frame, a portion of the lowerwall of the concave forming portion is opened and, further, the fixingjig is a cotter, wherein the cotter is inserted from above between theportion of the moving device and the shorter side frame.
 9. A continuouscasting mold as defined in claim 8, wherein the shorter side frame hascooling water channels at the inside thereof.
 10. A continuous castingmold as defined in claim 8, wherein a supply port and/or discharge portof the cooling water channel is disposed to the upper end part of theshorter side frame.
 11. A method of exchanging, in-situ, a pair ofengaged shorter side frames (referred to as A) with another pair ofshorter side frames (referred to as B) in a continuous casting moldhaving: a pair of longer side frames in which at least one of the longerside frames is movable in a forward-to-backward direction, a pair ofshorter side frames put between the pair of the longer side frames andmovable in the forward-to-backward direction and moving devices engagedby way of one or more of attachment/detachment mechanisms disposed tothe shorter side frames respectively for moving the shorter side framesin the forward-to-backward direction wherein the method comprises; astep of once stopping casting, a step of moving the shorter side framesA by the moving devices in the forward-to-backward direction andstopping the shorter side frames A at predetermined exchange positions,respectively, a step of moving at least one of the longer side frames toan aimed position in a forward-to-backward direction thereby setting anaimed slab thickness, a step of releasing the attaching/detachingmechanisms respectively for the shorter side frame A to detach theentire shorter side frames A from the moving devices respectively, astep of engaging the entire shorter side frames B having a widthcorresponding to the aimed slab thickness to the moving devices by wayof the attaching/detaching mechanisms for the shorter side frames Brespectively, a step of moving the shorter side frames B by the movingdevices respectively in the forward-to-backward direction therebysetting a predetermined slab width and a step of starting casting again,wherein each of the at least one of the attaching/detaching mechanismshas a concave forming portion having a concave portion engaging aportion of the moving device, and at least one of theattaching/detaching mechanisms has a fixing jig for fixing the portionof the moving device to the concave forming portion on every shorterside frame, and wherein the concave forming portion has a downwardopening portion, and the fixing jig is a bolt screw passing from abovethrough the back of the concave forming portion and at least a portionof the moving device.
 12. A method of exchanging the shorter side framesin-situ in a continuous casting mold defined in claim 11, wherein themethod includes a step of stopping the supply of cooling water to theshorter side frames A before detaching the shorter side frames A fromthe moving devices, respectively, and detaching the supply pipes forcooling water to the shorter side frames A from the shorter side framesA respectively and further includes: a step of connecting the coolingwater supply pipes to the shorter side frames B respectively afterengagement of the shorter side frames B to the moving devices, andstarting supply of cooling water to the shorter side frames Brespectively.
 13. A method of changing the thickness of a continuouslycasting slab comprising a step of exchanging the shorter side frames bythe method defined in claim
 11. 14. A method of exchanging, in-situ, apair of engaged shorter side frames (referred to as A) with another pairof shorter side frames (referred to as B) in a continuous casting moldhaving: a pair of longer side frames in which at least one of the longerside frames is movable in a forward-to-backward direction, a pair ofshorter side frames put between the pair of the longer side frames andmovable in the forward-to-backward direction and moving devices engagedby way of one or more of attachment/detachment mechanisms disposed tothe shorter side frames respectively for moving the shorter side framesin the forward-to-backward direction wherein the method comprises; astep of once stopping casting, a step of moving the shorter side framesA by the moving devices in the forward-to-backward direction andstopping the shorter side frames A at predetermined exchange positions,respectively, a step of moving at least one of the longer side frames toan aimed position in a forward-to-backward direction thereby setting anaimed slab thickness, a step of releasing the attaching/detachingmechanisms respectively for the shorter side frame A to detach theentire shorter side frames A from the moving devices respectively, astep of engaging the entire shorter side frames B having a widthcorresponding to the aimed slab thickness to the moving devices by wayof the attaching/detaching mechanisms for the shorter side frames Brespectively, a step of moving the shorter side frames B by the movingdevices respectively in the forward-to-backward direction therebysetting a predetermined slab width and a step of starting casting again,wherein each of the at least one of the attaching/detaching mechanismshas a concave forming portion having a concave portion engaging aportion of the moving device, and at least one of theattaching/detaching mechanisms has a fixing jig for fixing the portionof the moving device to the concave forming portion on every shorterside frame, and wherein the opening of the concave forming portion isdirected to the back of the shorter side frame, a portion of the lowerwall of the concave forming portion is opened and, further, the fixingjig is a cotter, wherein the cotter is inserted from above between theportion of the moving device and the shorter side frame.
 15. A method ofexchanging the shorter side frames in-situ in a continuous casting moldas defined in claim 14, wherein the method includes a step of stoppingthe supply of cooling water to the shorter side frames A beforedetaching the shorter side frames A from the moving devices,respectively, and detaching the supply pipes for cooling water to theshorter side frames A from the shorter side frames A respectively andfurther includes: a step of connecting the cooling water supply pipes tothe shorter side frames B respectively after engagement of the shorterside frames B to the moving devices, and starting supply of coolingwater to the shorter side frames B respectively.
 16. A method ofchanging the thickness of a continuously casting slab comprising a stepof exchanging the shorter side frames by the method defined in claim 14.